Volvo 240/740/760/780/940/960 1990-1998

Alternator

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TESTING



Voltage Test
  1. Make sure the engine is OFF , and turn the headlights on for 15-20 seconds to remove any surface charge from the battery.
  2.  
  3. Using a DVOM set to volts DC, probe across the battery terminals.
  4.  
  5. Measure the battery voltage.
  6.  
  7. Write down the voltage reading and proceed to the next test.
  8.  

No-Load Test
  1. Connect a tachometer to the engine.
  2.  


CAUTION
Ensure that the transmission is in Park and the emergency brake is set. Blocking a wheel is optional and an added safety measure.

  1. Turn off all electrical loads (radio, blower motor, wipers, etc.)
  2.  
  3. Start the engine and increase engine speed to approximately 1500 rpm.
  4.  
  5. Measure the voltage reading at the battery with the engine holding a steady 1500 rpm. Voltage should have raised at least 0.5 volts, but no more than 2.5 volts.
  6.  
  7. If the voltage does not go up more than 0.5 volts, the alternator is not charging. If the voltage goes up more than 2.5 volts, the alternator is overcharging.
  8.  

Usually under and overcharging is caused by a defective alternator, or its related parts (regulator), and replacement will fix the problem; however, faulty wiring and other problems can cause the charging system to malfunction. Further testing, which is not covered by this guide, will reveal the exact component failure. Many automotive parts stores have alternator bench testers available for use by customers. An alternator bench test is the most definitive way to determine the condition of your alternator.

  1. If the voltage is within specifications, proceed to the next test.
  2.  

Load Test
  1. With the engine running, turn on the blower motor and the high beams ( or other electrical accessories to place a load on the charging system).
  2.  
  3. Increase and hold engine speed to 2000 rpm.
  4.  
  5. Measure the voltage reading at the battery.
  6.  
  7. The voltage should increase at least 0.5 volts from the voltage test. If the voltage does not meet specifications, the charging system is malfunctioning.
  8.  

Usually under and overcharging is caused by a defective alternator, or its related parts (regulator), and replacement will fix the problem; however, faulty wiring and other problems can cause the charging system to malfunction. Further testing, which is not covered by this guide, will reveal the exact component failure. Many automotive parts stores have alternator bench testers available for use by customers. An alternator bench test is the most definitive way to determine the condition of your alternator.

REMOVAL & INSTALLATION



On some models, it will be necessary to remove the air pump and position it to one side to gain access to the alternator.

Except 850/C70/S70/V70
  1. Disconnect the negative battery cable.
  2.  
  3. Loosen the alternator adjusting bolts (if equipped).
  4.  
  5. Remove the drive belt from the alternator pulley.
  6.  
  7. Disconnect the electrical leads to the alternator.
  8.  
  9. Remove the alternator adjusting bolts (if equipped) and mounting bolts.
  10.  
  11. Remove the alternator from the vehicle.
  12.  

To install:
  1. Install the alternator into the bracket.
  2.  
  3. Install the mounting bolts and the adjusting bolts (if equipped).
  4.  
  5. Tighten the mounting bolts only and, if equipped, leave the adjusting bolts loose.
  6.  
  7. Connect the electrical leads to the alternator.
  8.  
  9. Install the drive belt around the alternator pulley.
  10.  
  11. Adjust the tension on the belt (non-serpentine) as outlined in General Information & Maintenance and tighten the adjusting bolts (if equipped).
  12.  
  13. Connect the negative battery cable.
  14.  
  15. Verify the operation of the alternator.
  16.  

850/C70/S70/V70

See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the drive belt from the engine.
  4.  
  5. Remove the power steering pump and tensioner bracket mounting bolts, then lift the assembly up and rest it on top of the engine.
  6.  
  7. Disconnect the electrical leads to the alternator.
  8.  
  9. Remove the alternator mounting bolts.
  10.  
  11. Remove the alternator from the vehicle.
  12.  

To install:
  1. Install the alternator onto the engine and tighten the mounting bolts.
  2.  
  3. Connect the electrical leads to the alternator.
  4.  
  5. Install the power steering pump and tensioner bracket and tighten the mounting bolts.
  6.  
  7. Install the drive belt.
  8.  
  9. Connect the negative battery cable.
  10.  
  11. Verify the operation of the alternator.
  12.  



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Fig. Fig. 1: Release the tensioner ...



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Fig. Fig. 2: ... and remove the drive belt



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Fig. Fig. 3: Remove the mounting bolts from the bracket ...



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Fig. Fig. 4: ... and note their location for installation (they are different lengths)



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Fig. Fig. 5: After the bolts are removed, lift the bracket and place the alternator on top of the engine



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Fig. Fig. 6: Detach the electrical connectors from the back of the alternator



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Fig. Fig. 7: Remove the cover from the battery cable connection on the rear of the alternator ...



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Fig. Fig. 8: ... then unfasten and remove the cable from the alternator



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Fig. Fig. 9: Unfasten the alternator mounting bolts ...



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Fig. Fig. 10: ... and remove the alternator

 
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